A Gardening Journal
Today in the Garden of a Lifetime: American Beech Foliage in Winter
- Published: December 28 2012
Beech trees retain their Fall foliage until Spring, and so hedges of beech provide privacy year-round. The Winter foliage of such hedges—mine is of native beech, but all beech hedges are similar—is a warm russet.
The Winter foliage of native beeches growing in the woods, though, can vary a lot. The nearest one in the picture below has foliage the russet of beech hedges. The foliage of ones farther back is noticeably lighter.
I thought I knew the range of possibilities until I discovered this tree right along the road, a couple of miles from my house.
Its foliage is parchment white.
The contrast with the russet of beech-hedge foliage is stunning.
Why is the foliage of the beech by the stone wall so much lighter? And what might be done to encourage a beech growing in a garden to sport such foliage?
This much is certain: The difference between these two beeches isn't genetic. Both are American beeches, Fagus grandifolia, and that species is famously loathe to "radiate"—to mutate into forms that are different. European beeches, in great contrast, mutate with abandon. Truly, new forms of Fagus sylvatica seem to be discovered annually, and I myself am growing at least a half dozen of them. Plus, those forms can then be hybridized, resulting in still more weird-and-wonderful beeches. Ah, those Europeans.
But American beeches keep themselves to themselves. Any differences between the beech with parchment-white foliage and the beech with russet-brown foliage are the result of culture and handling: The conditions where each tree is growing, and what (if any) care each receives.
Let's compare the two trees in hopes of discovering what might account for their remarkably different foliage.
* The "russet beech" is pruned as part of a hedge, whereas the "parchment beech" gets no such care. But there are plenty of unpruned American beeches in the woods that also have russet foliage.
* Both trees are grown from seed, so there's no difference that might have resulted from one having been propagated by grafting. There are about 120 American beeches in my hedge, and all of them have not only the same russet foliage, they have the same shade of russet foliage. As I say, American beeches are consistent from seed.
* The parchment beech is growing on a steep slope, whereas my hedge is growing on nearly level ground. With my heavy soil, that means that the hedge has access to much more moisture than the parchment beech. The difference in leaf size, parchment beech to russett beech, may also relate to that.
* Perhaps most important is that I've never seen a parchment beech that wasn't growing in considerable shade. This one, true to form, is surrounded by trees. My beech hedge is growing in full sun.
Could a parchment beech be created in a garden, then, merely by siting it in the shade? If so, it could never be allowed to become full-size, because then it would be too large to shade. Also, beech trees retain Fall foliage only on their lower portions, so pruning a beech—whether into a hedge, or just informally, or into some other compact shape—is a handy way to keep the tree small enough that it will retain Fall foliage from top-to-bottom, as well as small enough to remain easily shaded.
As I mentioned in the article on columnar hornbeams, the term for retention of Fall foliage is "marcescence." The parchment beech could be thought of as an albino marcescent. Does any garden in the world have an albino marcescent that exists by intention instead of arising by chance?
How can there not be a place for one—for several!—in my gardens? Beeches are planted in Spring, so between now and then I'll rethink my gardens' plans to find a location for this experiment: Planting a few small American beeches in half-shade, and then keeping them pruned so that they remain small enough to stay shaded, and also so they take up the minimum space.
The parchment beech by the road couldn't be more than five or six years old, and my hunch is that it has been displaying albino marcescence for years. I've given the tree a discrete marking so I can be sure to monitor its display in years to come. Perhaps albino marcescence is also a factor of seasonal conditions. How else is it that I've never noticed this tree's radiant Winter display, when it's growing right along a road I travel several times a week?
What a cold-weather show it would be to have a ghostly-white group of clipped beeches. A trio, say, of albino marcescents. If I can launch this experiment in the Spring of 2013, there might be results by the Winter of 2016. Stay tuned.
Here's how to grow American beech. Once the factors that determine the color of the tree's marcescent foliage are known, I'll update the "How to handle" and "Culture" blocks.